What does tray mean in cooking?

tray means: Container made up of corrugated, chipboard, or open boxes wrapped in plastic film. (in Cooking Dictionary)

What else does tray mean?

• This is a shallow, flat container with raised edges or rims that can be used to carry, hold, or display articles. (in Merlin Dictionary)
• With its contents, a shallow flat container. (in Merlin Dictionary)